After hours of prep and hours of baking I managed to burn it! Rich fruit cake, started it on 150 C (fan assisted) for first hour then 130 for the next 3.5 hours. I wonder if it has anything to do with fact that I did not line tins with brown paper - used four layers of greaseproof or was oven just too hot?
I've pared the surfaces and am sprinkling liberally with rum and port - any other suggestion for rescuing?